Lock for metallic mine props



May 8, 1956 w. L. G. HEUSNER LOCK FOR METALLIC MINE PROPS I5 Sheets-Sheet 1 Filed Aug. 1, 1951 J/V/[IWUE l/i/be/m lady/: Gustav fleusner May 8, 1956 w. G. HEUSNER 2,744,717

LOCK FOR METALLIC MINE PROPS Filed Aug. 1, 1951 3 Sheets-Sheet 2 35/ @Qu h Aland Ajent.

May 8, 1956 w. L. G. HEUSNER LOCK FOR METALLIC MINE PROPS 3 Sheets-Sheet 3 Filed Aug. 1, 1951 INVENTOR [VI/helm lady/j aalav/Vegsner MQQA United Stat p H LOCK FOR METALLIC MINE PROPS Wilhelm Ludwig Gustav 'Heusner, Bochum, Germany, assignor to Hermann Schwarz K. G., Wattenscherd, Germany With two-part metallic mine props or stemples it is common knowledge to fix the two prop portions, an upper prop part and a lower prop part, relative to each otherin operating position by means of a prop lock, while, for purposes of robbing or abstracting the prop, the two prop portions are released so that they can telescope-relative to each other. In this connection it is alsoknown, when adjusting the mine prop in the prop lock, to .produce a tightening pressure by manually driving in a wedge andto make use of the overburden or drooping part pressure for increasing the said tightening pressure up-to a maximum value. To this end, a dragging member is frictionally coupled to the upper prop part so that the latter, when sinking downwardly, takes along the dragging member in the direction of movement of the upper'prop part. In order to assure such operation, it is necessary to produce a high friction between the respective contacting surfaces of the dragging member and the upper prop part, and to produce a low friction at the supporting surfaces of the dragging member. If this dragging member consists of a wedge, it is necessary that, in addition to maintaining a great difference in friction at the respective effective areas of the dragging member,

the angle or slope of the wedge must not exceed a predetermined value.

In order to create and maintain the above mentioned ditference in friction, it has been suggested to provide the dragging member at the surface facing the upper prop part with a cover or shoe having a high frictional coefficient, i. e. with a cover or shoe of wood or metal. Since the lock elements are generally forged parts with a rough surface, the difference in friction above referred to is only small and practically vanishes when rust forms.

" In an efiort to remedy this drawback, it has been suggested mechanically to smooth and to lubricate those pairs of surfaces between which a low fn'ctionis supposed to prevail. Such lubrication, however, remains effective only for a relative short period of time, so that it becomes necessary, at more or less short intervals to repeat the lubricating operation. To this end, however, the prop has to be taken apart completely into its individualelements, which causes considerable difficulties when mining underground.

'To remedy this drawback, an effort was made to create and maintain the desired frictional difierence by employing slidable sheet metal elements .of rustproof material which are freely but safely movable and are interposed between two adjacent lock members at an area where a sliding. movement is desired with aminimum of friction. However, this arrangement has not proved successful either, since due to the high pressure per area unit at the rather low speed at which the relative movement occurs, the metal sheets eat into each other and are thus mechanically damaged. In addition thereto, rust formation may occur between the outsides of the sheets and the elements contacting thesame. In orderto avoid this drawback, also with this arrangement, those pairs of areas between which a low friction is supposed to prevail, are likewise lubricated. However, since this lubrication has to be repeated from time to time, it is likewise necessary completely to dismantle the prop.

It is, therefore, an object of this invention, to provide a metallic mine prop or stemple, which will be free from the above mentioned drawbacks. v i

It is another object of this invention, to provide a metallic mine prop or stemple, in which those elements between which a low friction is desired, may effectively be lubricated without necessitating a dismantling of the prop.

It is a still further object of this invention to provide a metallic mine prop or stemple whichincludes a wedge arrangement'and in which the effective frictional surfaces that are not directly accessible from the outside of the arrangement, may conveniently be lubricated from the outside. 1 I

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings,

in which:

Fig. l represents a longitudinal section through a mine prop or stemple according to this'invention.

Fig. 2 is a section along the line II--II of Fig. 1. Figs. 3 and 5 illustrate the slidable sheet metal elements of a mine prop in two dilferent Working positions.

The lock according to the present invention, which includes a wedge arrangement and is intended for twopart metallic mine props, is. characterized in that they effective surfaces of the wedge arrangement which are in frictional engagement with each other and between which the friction has to be kept low,'communicate with passage means accessible from the outside of the arrangement and adapted to convey lubricating means from said outside to said surfaces. Preferably, these passage means are closed toward the outside by a nipple of any standard design. If an ordinary wedge arrangement is involved, i. e. a wedge arrangement without relatively slidable sheet metal elements, the said passage means include lubricating grooves within the above mentioned effective surfaces. If, on the other hand, a wedge arrangement is involved with slidable sheet metal members arranged between lock band and the follower or drag cation may be obtained without any longer necessitating a dismantling of the prop.

In order to prevent the lubricating means from being pressed outwardly unto areas where a high friction has to prevail, the lubricating passage means such as the above mentioned lubricating grooves or'the likewise above mentioned perforations or apertures in the slidable metal sheet members are, according to a further' development of this invention, arranged so that they will remain covered or overlapped by the adjacent lock elements in any possible positions of the lock members.

According to a still further development of the invention, the edge portions of the perforations or apertures" are so arranged that they will not overlap in any of the 1 possible positions. In this connection, it should be borne Patented May 8, p 1956 in mind that the slidable sheet metal members are subjected to rather high pressures. If during the working of the lock, the edge portions of the perforations or apertures would have to slide one over the other, compressions of the edge portions would be unavoidable. Since, when the follower or dragging wedge sinks downwardly, it is far more probable that it will be followed by the sheet metal member adjacent the dragging wedge rather than 'by the sheet metal member remote therefrom, a registering of the perforations or apertures with each other during the downward movement of the dragging wedge can be safely avoided by arranging the edge portions of the apertures of that sheet metal member which is adjacent saiddragging wedge, lower than those of the more remote sheet metal member or members.

Structural arrangement Referring now to the drawings in detail, the mine prop shown in Fig. 1, comprises a box-shaped lower part 1 representing the lower prop member in which the upper part 2 having an I-section is movably guided. Said upper "part 2 represents the upper prop member. Connected to the upper end of part 1, e. g. by welding, is the lock band or collar 3. The lock band 3 is provided with substantially horizontal slots 4 into which are inserted the eccentric bolt 5 and the substantially horizontally arranged wedge 6 which may also be termed the locking wedge. One area of the wedge 6 abuts and is supported by the area 7 of the eccentric bolt 5, while the opposite area :of wedge 6 abuts a friction or pressure member 8 which may also be called a bolster. The plane 9 of member 8 rests on a support 10 which is rigidly connected to the lower part or lower prop member 1. The pressure member 8 is located between the legs of the upper part or upper prop member 2 and engages the area'12 (Figs. 1 and 7) of the web of the I-beam of upper prop member 2 by means of a frictional cover or shoe 11. On the opposite side of the web of said I-beam, there is provided a follower wedge or dragging wedge 13 which is likewise located between the legs of the I-beam and which engages the area of the web of the I-beam. The lock band 3 is provided with a slant surface 19 against which the rear surface 16 of wedge 13 rests 'throughthe intervention of the slidable sheet metal members 17 and 18. In vertical direction, wedge 13 rests ona spring which latter is supported by a support 21 inserted into and rigidly connected to the lower "part 1. The support 21 is provided with an aperture 21a through which movably extends a rod 22 operatively connected to the wedge 13 for guiding=the:same.

'When installing the mine :prop, the elements 1 to 22 occupy the respective positions shown in Fig. 1. Assuming these positions, it will be clear that by driving the wedge 6 inwardly, the friction shoes 11 and 14 are pressed against the webof the upper part 2, so that the upper part 2 is frictiona'lly arrested in its position. It now the :pressure of the roof or overburden increases to such an extent that the friction of the upper part in the prop lock doesnot sutrice any longer to resist the pressure, the upper part 2 will be pressed into the lower part 1. During this action, a relative movement occurs between the surface 12 of the upper part 2 and the friction shoe 11 which is stationary in vertical direction and pertains to the pressure member 3. On the other hand, the wedge 13 is taken along downwardly due to the friction between friction shoe 14 and the area 15 of the upper part 2. This action, however, will occur only if the friction between the surface 16 of wedge 13, the slidable members 17, 18, and the surface 19 of the lock band 3 is less than the friction between the friction shoe 14 and the surface .15 of the upper part2, and if, furthermore, the angle of inclination of wedge 13 is less than the. angle of friction. in order to maintain a low frictional value between the above mentioned surfaces, ac-

cording to hsrr s ent ubr cat n me ns. is pressed between these surfaces through the lubricating nipple 23 and the aperture 24. The slidable sheet metal members 17 and 18 are provided with perforations or apertures 25 and 26 respectively into which lubricating means is pressed. Furthermore, according to another feature of this invention, the apertures 25 and 26 are so arranged that at all operative positions, the said apertures remain covered by the adjacent lock elements, so that no lubricating means can escape toward the outside.

It should also be noted that the edge portions 27 and 28 of the apertures 25 and 26 are disposed in offset arrangernent with regard to each other. Thus, the edge portions 27 of the aperture 25 are located lower than the edge portions 28 of the aperture 26. In view of this arrangement, the edge portions 27 of the aperture 25 can never register with or overlap the edge portions 28 of the aperture 26, so that these edge portions cannot abut each other, and, consequently, the sheet metal members 17 and 1 8 cannot eat into each other.

Figs. 1 and 2 illustrate the location of the apertures 25 and 26 when the members 17 and 18 are in their starting position. Figs. 3 and 4 show the sheet metal member 17 in its lower end position, whereas the sheet metal member '18has retained its starting position. Figs. 5 and 6 show bothslidable sheet metal members in their lower end positions. As will be clear from the drawing, in these possible extreme positions, the apertures 25 and 2e are always covered by 'adjacent'lock members, and in none of these positions do the edge portions 27 and 28 register with-each other.

It is, of course, understood that the present invention ary whensaid assembly is in its operative position, said upper mine prop member being providedwith oppositely located friction surfaces, a first friction member :and. a second friction member substantially facing each other and respectively fric't-ionally engaging said .oppositely'located friction surfaces, .rigid abutment means supportedby said lower prop member and engaging said first friction member to thereby prevent the same from moving downwardly with the :downward movement of :said upper prop member, yieldable supporting means supported by said lower prop member and yieldabl-y supporting said secondfriction member to allow the latter to move-downwardly with-the upper prop member, clamping pressure exerting means including a stationarymember connected to the lower prop member and having a surface facing said second friction member, said clamping pressure exerting means also including means arranged for cooperation. with said stationary member and to convey pressure tosaid first andsecond friction members, and pressure conveying means slidably arranged between and engaged by said second friction member and said-surface of said stationary member and having passage means therethrough arranged to store lubricatingmeans and to convey the same to said second friction member. 7

2. In combination in a lock arrangement for a mine prop: a lower prop member, an upper prop member movably extending into said lower prop member, a friction member frictiona'lly engaging one side of said upper prop member, a follower wedge frictionally engaging the op: posite side of said upper prop member and movable together therewith, abutment means connected to said lower prop member and engaging said friction member to' thereby prevent said friction member from moving with said upper prop member when the'latter moves into said lower prop member and yieldably supporting said follower wedge, plate means engaging said follower wedge and provided with lubricant storing and conveying passage means accessible from the outside of said lock arrangement and arranged to convey lubricant to that surface of said plate means which is in contact with said follower wedge for reducing the friction therebetween over the friction between said follower wedge and said upper prop member, and clamping means supported by said lower prop member and operable to press said friction member against said upper prop member and-also to press said plate means against said follower wedge and thereby the latter against said upper prop member.

3. In combination in a lock arrangement for a mine prop having a lower prop member and an upper prop member telescopically movable into said lower prop member, a friction member frictionally engaging one side of said upper prop member, a follower wedge. frictionally engaging the opposite side of said upper prop member, supporting means rigidly connected to said lower prop member and supporting said friction member, pressure exerting means engaging said friction member and operable to bring said friction member into frictional en gagement with said upper prop member, yielding means supported by said lower prop member and yieldably supporting said follower wedge, and plate means having a surface slidably contacting said follower wedge and provided with lubricating passage means accessible from the outside of said lock arrangement and adapted to hold and convey lubricating means between contacting surfaces of said plate means and said follower wedge for reducing the friction between said last mentioned conand to presssaid follower wedge against said opposite surface through said lock band and said sheet metal members, said lock band being provided with a passage communicating with said passage means for conveying lubricating means thereto.

5. In combination in a mine prop assembly having a lower prop member and an upper prop member movable into said lower prop member, a lock band adjacent said upper prop member and connected to said lower prop member, a friction member arrangedwithin said lock band and operable frictionally to engage one surface of said upper prop member, a follower wedge arranged within said lock band and operable frictionally to engage another surface of said upper prop member, said I follower wedge and saidlock'band respectively being provided with slant surfaces facing each other, two sheet metal member interposed between and slidably engaging said slan t surfaces and being slidable relative to each other, said-sheet metal members being provided with passage means for passing lubricating means therethrough, the lower and upper edge of the passage means lock bandtoward the outside of said mine prop assembly,

- lock band and said friction member and operable to press tacting surfaces over the friction between said follower I ranged that in any relative position'of said sheet metal member, a friction member arranged within said lock band and frictionally engaging one surface of said upper prop member, a follower wedge arranged within said lock band and frictionally engaging the opposite surface of said upper prop member, supporting means supporting said friction member and forming an abutment for the latter, said follower wedge and said lock band respectively being provided with slant surfaces facing each other, a pair of slidable sheet metal members interposed between and slidably engaging said slant surfaces, said sheet metal members slidably engaging each other and being provided with passage means therethrough for storing and conveying lubricating means, and a wedge member arranged for cooperation with said lock band and said firction member and operable to press said friction member against said one surface of said upper prop member and a wedge member arranged for cooperation with said said friction member againstsaid one surface of said upper prop member and to press said follower wedge against said other surface ofsaid upper prop member through said lock band and said sheet metal members.

6. An assembly according to claim 5, in which the passage .means in said sheet metal members are so armembers the respective lower and upper end portions of the passage means in the sheet metal member adjacent said follower wedge are located lower than the corresponding lower. and upper end portions of the passage means in the sheet metal member remote from said follower wedge.

References Cited in the file of this patent UNITED STATES PATENTS 2,021,272 Toussaint Nov. 19, 1935 2,548,229 Mendenhall Apr. 19, 1951 FOREIGN PATENTS 611,261. Great Britain Oct. 27, 1948 642,566 France Aug. 31, 1928 677,122 Great Britain Aug. 13, 1952 I 934,603 France May 27, 1948 

